WO1991006810A1

WO1991006810A1 - Radiant tube with internal modules

Info

Publication number: WO1991006810A1
Application number: PCT/FR1990/000770
Authority: WO
Inventors: Franck Duverger
Original assignee: Gaz Industrie
Priority date: 1989-10-25
Filing date: 1990-10-24
Publication date: 1991-05-16
Also published as: KR0139283B1; JP3147379B2; FR2653536A1; IT9067819A0; IT1242725B; JPH04504302A; KR920701760A; FR2653536B1; IT9067819A1

Abstract

Space heating. The radiant tube heating device, of a type to be suspended or mounted at high level in a building, is characterized by the design of module (15) causing a progressive increase in the internal cross-section of the radiant tube from its end attached to the burner (5). Application: industrial or commercial space heating.

Description

RADIANT TUBE WITH INTERNAL MODULES

TECHNICAL AREA :

The present invention relates to the general technical field of heating devices for buildings of the industrial type and relates, more particularly, to gas heating devices of the radiant tube type.

Radiant tube devices are commonly used for heating industrial and commercial buildings and are, most of the time, suspended at a certain height in the building under consideration. They can also be held in place against elements of partitions or the like. These devices, which emit infrared radiation at low temperature, are used to provide global and zone heating.

PRIOR TECHNIQUE:

A first type of installation is known comprising a single heating circuit, generally monotube, of shape and dimension adapted to the conformation and the volume of the space to be heated. These installations, the width of which may be significant, of the order of 30 meters, require, because of their length, the presence of several heating units, comprising at least one burner, distributed along the heating circuit, in order to maintain a temperature emission as homogeneous as possible in the room. An extractor is mounted at the end of the circuit and ensures the circulation of the combustion gas, as well as the quality thereof. These installations turn out to be a delicate installation, due to their complexity of installation, since they are not removable, and their specificity, these installations being, in fact, not of standard type they do not do not allow, moreover, to modulate the temperature along the heating circuit. To overcome these drawbacks, it has been proposed to produce heating installations with radiant tubes comprising several individual heating units distributed more or less regularly throughout the building to be heated. Each unit comprises a main block comprising the gas burner and an extractor comprising an extraction turbine. The burner is connected to the extraction unit, via a tube resistant to high temperatures and which constitutes the radiant tube itself. The latter can extend over a length of up to 6 meters and forms a U-shaped circuit between the burner and the extraction turbine. The heating device generally comprises, in addition, a reflection casing, of "U" cross section, disposed above the circuit of the radiant tubes and laterally covering the latter. The device is completed by a device stiffening assembly and by fixing and suspension systems of the heating unit.

The presence of several individual heating units allows room temperature control and temperature modulation in privileged areas of the room to be heated. The limited size of these individual units also facilitates the general implementation of the device. The operation of this type of installation, if it is generally considered satisfactory, has certain drawbacks. In the first place, it is worth mentioning the difficulties posed when it proves desirable to lengthen the heating circuit, by assembling one or more portions of modular tube. These devices are, in fact, designed for a determined length, of the order of 8 to 10 meters, and the extension of the heating circuit requires, correlatively, an increase in the power of the burner. These modifications lead, despite the presence of an extraction unit, to a very high tube temperature, of the order of 600 C near the burner, that is to say along the part of the tube licked. by The burner flame. Temperature uniformity along the radiant tube, is no longer ensured, which obviously affects the overall thermal performance of the device and negatively influences the performance of the device. This drawback is also found in the first type of device mentioned above. The comfort of the user is also affected, since the temperature of the room is then heterogeneous.

Furthermore, it proves difficult to increase, in large proportions, the heat emission of the device, insofar as the increase in power of the burner always results in a heterogeneous rise in temperature Along the tube and causes a variation of the infrared wavelength.

Also known from US Pat. No. 4,529,123 is a heating device comprising a burner associated with the end of a radiant tube inside which has been inserted, at a distance from the internal surface. of the tube, a tubular insulating sleeve. Such an insulating sleeve promotes, to a certain extent, the homogenization of the temperature along the tube in its position adjacent to the burner. The homogenizing effect is, however, incomplete and does not take into account the axial temperature gradient caused by the burner flame, since the thickness of the sleeves is constant. Furthermore, in the case of very long installations comprising large capacity burners, it is necessary to have recourse to internal sleeves of large length, which increases, in proportion, the cost of the installation and negatively influences the circulation and combustion of the air inside the tube, due to the reduction in the cross-section of the tubes over portions of large lengths.

The object of the present invention is to remedy the drawbacks of the devices described above and to produce a heating device in which the temperature, along the entire circuit formed by the radiant tubes, is as homogeneous as possible.

Another object of the invention consists in producing a heating device with radiant tubes which avoids excessive heat. temperature of the tube near the burner and which allows an extension of the burner flame.

Another object of the invention consists in proposing a heating device with radiant tubes with improved thermal efficiency.

Another object of the invention consists in producing a heating device with radiant tubes in which the overall emission of heat radiation, by the radiant tubes, is improved.

STATEMENT OF THE INVENTION

These objectives are achieved by means of a heating device with radiant tubes, of the type intended to be suspended or fixed in height in a building, comprising at least one radiant tube associated, at one end, with a gas burner block, emitting a flame. , the interior of the radiant tube being lined, from its end associated with the burner block, with at least one module in the form of a hollow jacket extending over a length portion of the radiant tube, characterized in that the module has a conformation intended to gradually increase the internal section of the radiant tube, from its end associated with the burner.

Various other characteristics appear from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the object of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS:

Fig. 1 shows a general perspective view of a heating device with radiant tubes provided with an insulating reflection casing.

Figs. 2, 2_ and 3 show views of variants of the invention according to a longitudinal section of a portion of the radiant tube associated with the burner. Figs. 4 and 5 represent cross sections of the radiant tube, taken, respectively, along the lines IV-IV of FIG. 2 and VV of fig. 3.

Figs. 6 and 7 show cross sections of the radiant tube illustrating two different embodiments.

Fig. 8 shows a perspective view and in a cross section of a heating unit according to the invention, in which the tubes are isolated from each other, at least in part.

Fig. 9 shows a top view of the end of a heating circuit according to the invention.

Figs. 10 and 11 show, respectively, a perspective view and a cross-sectional view of connecting members interposed between two radiant tubes.

BEST WAY TO IMPLEMENT THE INVENTION:

Fig. 1 shows, in exploded view, a heating unit 1 consisting of a heating assembly 2 proper and of an insulating and reflective casing 3. The heating assembly 2 comprises a main housing 4 in which the various elements are arranged necessary for controlling the heating unit 1, namely, for example, the electronic control and regulation circuits, the safety solenoid valves, the ignition and control systems. The main unit 4 is extended by two separate cowlings forming a burner block 5 and an extractor block 6 containing, respectively, the burner proper 7 and an extraction turbine provided with its drive motor.

The burner block 5 and the extractor block 6 are connected by means of a closed circuit consisting of a tubular element forming the radiating member. In the example, shown in fig. 1, the radiating member forms a U-shaped circuit composed of several tubular elements 8-, 8- ,, 8 ,, 9_., 9_, 9, extending in substantially parallel and connected planes, respectively, by one of their ends, to the block burner 5 and to the extractor block 6. These different tubular elements are connected together or placed end to end to constitute the radiation assembly composed of the radiant tubes 8, 9. The radiation assembly may, of course, not be composed that a limited number of tubular elements 8, 9 and, at a minimum, two are sufficient. The ends of the radiant tubes 8 and 9 are connected to each other by means of an elbow 10. In the example shown in FIG. 1, the radiant tubes are straight lines and cylindrical, but it is obvious that tubes of various sections can be used and that the shape of the circuit can also vary.

It is also possible to envisage making a heating device without an extraction circuit.

The radiant tubes 8 and 9 are, in a manner known to those skilled in the art, made of a material particularly resistant to high temperatures.

The radiant tubes 8 and 9 are covered, over their entire length, by the insulating and reflective casing 3, which can be produced in several elements 3-., 3 _? , 3, corresponding to the different tubular elements which make up the radiant tubes 8,. 9. The casing 3 also has a "U" cross section comprising an upper face 3 and two lateral faces 3b, 3_c. The insulating and reflective casing 3 extends along an axis in the same direction as the longitudinal axes _A, _ _ of the tubes 8 and 9 and is provided, at one of its ends, with a closing wall 3j. The insulating and reflective casing 3 is intended to be placed in abutment against the main housing 4 or against the burner block 5 and the extractor block 6, on one side, and also, preferably, against a stop 12 arranged on the elbow 10 , on another side. The insulating and reflective casing 3 thus ensures a partial coating of the radiant tubes 8, 9 capable of promoting a privileged downward diffusion of infrared radiation.

In the case of using the heating units 1 as suspended heating devices, provision is made to equip the radiant tubes with the aid of suspension collars 13 enclosing the radiant tubes 8 and 9. It is then necessary to provide, for example, in combination with the collars 13, support strips 14 fixed under the collars 13 and arranged under the tubes 8, 9. The heating unit 1 is suspended by a suspension device 14 including, for example, a rope connected to a support pin fixed directly to the insulating casing and reflector 3.

The interior of the radiant tube 8, in direct relation with the burner 7, is lined, from its end associated with the burner 7, of a module 15 in the form of a hollow jacket. This sleeve lines the inner surface of the tube 8 and can extend over a portion of variable length. The module 15 preferably extends over a length substantially equivalent to the length of extension of the flame 16 of the burner 7. The module 15 can, of course, have a length greater or less than the length of the flame 16.

The module 15 is in the form of a hollow jacket adapting exactly to the dimensions and the conformation of the internal section of the radiant tube 8 and comprising a thickness delimiting an internal conduit 17 to the module 15. The lining of the interior of the radiant tube 8 by the module 15 therefore leads to a modification of the internal section of the tube 8 over the portion of length corresponding substantially to the length of the flame 16.

Fig. 2 shows a first exemplary embodiment in which the module 15 consists of a plurality of section reducing modules. On a first portion of its length, corresponding to the part closest to the burner 7, the radiant tube 8 is lined with three modules, respectively 5 _* , 15 15 ,, concentric and coaxial, nested respectively in each other, as illustrated in fig. 4. The tube portion 8, adjacent to the previously defined portion, is lined with two modules, respectively 15, 15_- concentric and fitted one into the other. This second series 15 ,, 15 ^ is in an end-to-end junction position with the first series 15 _* ,. 15 ^, 15, of modules. An additional packing module 15 can be disposed inside the tube 8, Following and contiguously, with The second series 15 ,, 15 ₅ of the modules. One obtains, in this way, an uninterrupted set of modules which, by means of interlockings and successive junctions, lead to a progressive increase in the internal section of the radiant tube 8, through the increase in section of the channel. internal 17 to module 15.

The reduction modules are generally made of a ceramic fiber material and can be force-fitted, for example.

Fig. 3 illustrates a second embodiment in which the reduction module 15 consists of a single jacket, the thickness variation of which is provided in such a way that the internal channel 17 in the module 15 increases progressively continuously. The internal section of the radiant tube 8 is therefore also modified in a direction of increase along the portion of the radiant tube 8 licked by the flame 16 of the burner 7.

Figs. 6 and 7 show other alternative embodiments within the scope of the present invention. It is thus possible to produce reduction odles 15 whose internal channel 17, delimited by the thickness of the module 15, is off-center with respect to the longitudinal axis of the module in the form of a sleeve. In the example shown for information, the longitudinal axis _M of the sleeve 15 is located at a lower level relative to the central Longitudinal axis _A of the tube 8, thereby creating a differential insulation of the tube 8 causing, in the case shown for reference in fig. 6, an over-insulation of the upper part of the tube 8. Other configurations are possible. In this way, an internal section of the radiant tube is obtained, of reduced diameter and the positioning of which, inside the tube, can be controlled. It is also possible to vary the conformation of the internal channel 17 which can take a section of cylindrical, square, triangular, hexagonal or diamond shape for example. It is, of course, possible to combine a specific form with a eccentric position of channel 17, in order to more or less isolate part of the tube.

The presence of reducing modules in the internal section of the combustion chamber, in the area licked by the burner flame, allows temperature control in the portion of the radiant tube 8 subjected to the highest temperature. Thanks to the gradual increase in the internal section of the combustion chamber, the temperature of the tube can be maintained at a temperature generally less than 400 ° C. on the external surface of the tube. Furthermore, the increasing increase in the internal section of the combustion chamber causes a Venturi effect inducing an additional stretching of the flame. This Venturi effect creates an additional factor positively influencing the temperature homogenization in the radiant tube, as well as combustion.

Fig. 2_a illustrates another alternative embodiment which does not differ from that presented in FIG. 2, only by the interposition of mounting wedges 31 between the internal surface of the tube 8 and the external surface of the modules 15. The wedges 31 can be cylindrical and annular, or in the form of cubes for example, arranged in a spaced apart position. periphery of the modules 15. The shims 31 ensure the blocking in position of the modules, when, in order to reduce the cost of installation, the sleeves, and for example those bearing the references 15-, 15-, and 15, of the fig. 2 are deleted. The terminal sleeve, not shown in FIG. 2_a, can be in total contact with the internal surface of the tube 8 and thus ensure its upholstery, total or partial and then require the interposition of a wedge 31. The lining of the sleeves 15 can thus be total or partial depending on the mode of production. Fig. 8 illustrates a particular configuration of the heating device. The insulating and reflective casing 3 is made of an insulating material 18 sandwiched between the two sheets constituting the insulating and reflective casing 3. It is also possible, as shown in FIG. 8, to provide the insulating and reflective casing 3 with a partition wall 19 extending in the longitudinal direction of the insulating casing 3, between the two radiant tubes 8 and 9. This wall 19, the function of which is to avoid or reduce the mutual radiation of the radiant tubes 8 and 9, can extend over a height of separation equivalent to the overall height of the radiant tubes 8 and 9 or, on the contrary, as shown in the example of FIG. 8, the wall 19 can extend over a height such that it partially intercepts the radiation from each of the tubes 8, 9 and, for example, half. In the latter case, the wall 19 extends substantially from the upper face 3_a of the insulating and reflective casing 3, to the central and longitudinal axes ^, _A ^ _ of each of the two radiant tubes 8 and 9. The wall 19 is , obviously, preferably parallel to the other two faces 3b and 3_ £ of the insulating casing 3. The lower half-circumference of each of the radiant tubes 8 and 9 is advantageously covered with a material 21 capable of promoting the thermal diffusion of tubes. It can be, for example, a coating based on paint capable of imparting, to the lower half-circumference. The particular behavior of a black body. This proposal, which leaves the alumina tube without any coating in its upper half-circumference, has the advantage of promoting thermal emissivity in the lower part of each of the tubes, while the thermal emissivity in the upper part is also reduced. as possible. This arrangement therefore ensures a non-negligible improvement in the overall efficiency of the device, by favoring direct radiation to the detriment of indirect radiation which is also subjected to a cooling effect due to its path in the air. Fig. 9 shows that, in the particular and preferential case of using a radiant circuit in the shape of a "U", the tubes 8 and 9 are interconnected by means of a flexible elbow 10. By this, the expansion of the entire device can be exercised freely, which helps relieve the structure of the entire device and increases the service life, otherwise of the device as a whole, at least of certain parts.

Fig. 10 illustrates an embodiment according to the invention, used when the length of the circuit of the radiant tubes must be increased. It is then planned to insert, inside the radiant tubes 8, 9, a hollow connection sleeve 22 which therefore has a shape complementary to that of the tubes 8, 9, apart from assembly and interlocking play.

In the example shown, the tubes being cylindrical, the sleeve 22 is also cylindrical and it comprises, substantially in a central zone, an outer ring 23 delimiting two interlocking half-cylinders 22a and 22b. The external ring 23 forms a protuberance with respect to the external envelope of the sleeve 22 and constitutes a stop against which the transverse sections of each of the tubes 8, 9 come to bear.

It is thus possible, thanks to the interposition of the sleeves 22, to lengthen the heating circuit and to make it compatible with the power of the burner, when the latter has been modified. It is, of course, possible to incorporate several additional tube modules. There are thus available, using section reducing modules and connection sleeves, means which are particularly simple to implement and reliable, allowing homogeneous heat emission along the tube and modification of the heating circuit. It is therefore particularly convenient to modify an existing installation.

It is also possible to provide for the use of radiant tubes 8 or 9 provided, at their connection ends, with collars folded down 24 (fig. 11), these tubes then being interconnected at these same ends by means of a collar 25 connecting able to enclose and surround the folded collars 24 of two adjacent tubes to ensure their tight connection. The interposition of a flexible elbow 10, between the tubes 8 and 9, is then necessary to take into account the expansion of the assembly.

All the technical proposals disclosed in the present invention also make it possible to carry out a radiant tube heater in which temperature variations along the entire circuit of the radiant tubes are minimized, while temperature control and thermal emission zones are improved.

BEST WAY TO IMPLEMENT THE INVENTION:

The invention can be implemented in industrial type buildings or for sports or commercial use and used as radiant heating.

The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope.

Claims

CLAIMS:

1 - Heating device with radiant tubes, of the type intended to be suspended or fixed in height in a building, comprising at least one radiant tube (8, 9) associated, at one end, with a gas burner block (5), emitting a flame (16), the interior of the radiant tube (8, 9) being lined, from its end associated with the burner block (5), with at least one module (15) in the form of a hollow jacket s' extending over a portion of the length of the radiant tube (8), characterized in that the module (15) has a conformation intended to gradually increase the internal section of the radiant tube (8, 9), from its end associated with the burner ( 5).

2 - Device according to claim 1, characterized in that the module (15) lines, at least in part, the internal surface of the tube (8).

3 - Device according to claim 1 or 2, characterized in that the module (15) extends over a length corresponding to the length of the flame (16) emitted by the burner block (5).

4 - Device according to claim 1 or 2, characterized in that the increase in section is continuous.

5 - Device according to claim 1 or 2, characterized in that the increase in section is discontinuous. 6 - Device according to one of claims 2 to 5, characterized in that the module (15), in the form of a shirt, comprises at least two shirts fitting one into the other.

7 - Device according to claim 6, characterized in that mounting wedges (31) are interposed between the jackets and the internal surface of the tube (8).

8 - Device according to claim 6, characterized in that the module (15) comprises at least two series of jackets in the end-to-end junction position in the tube (8).

9 - Device according to one of the preceding claims, characterized in that the tubes ⁽ 8, 9) and the shirts ⁽ 15) are cylindrical and coaxial.

10 - Device according to one of the preceding claims, characterized in that the shirts are made of molded ceramic fiber. 11 - Device according to one of the preceding claims, characterized in that it comprises two parallel radiant tubes (8, 9 ⁾ arranged in a pin and connected at their ends by a flexible elbow (10).

12 - Device according to one of the preceding claims, characterized in that the radiant tubes (8, 9) are covered externally, on their lower half-circumference, by a coating (21) capable of promoting the emission of heat.

13 - Device according to claim 12, characterized in that it comprises a reflective and insulating casing (3), open on a face containing the radiant tubes (8, 9) and consisting of rock wool sandwiched between two sheets, said radiant tubes being separated, in the longitudinal direction, by a reflective wall (19) forming part of the casing (3).

14 - Device according to claim 13, characterized in that it is suspended using a suspension device (14) connected directly to the reflective and insulating casing (3).

15 - Device according to claim 1, characterized in that there is provided a hollow connection sleeve (22) interposed between two tubes (.8, 9) and nestable, respectively, inside the two tubes (8, 9 ).

16 - Device according to claim 15, characterized in that the connection sleeve (22) has an external protuberance (23) delimiting two half-sleeves (23a_, 23b).

17 - Device according to claim 1, characterized in that one uses radiant tubes (8, 9) provided with collars folded (24) at their ends, said tubes being connected together by means of connecting collars (25) to those same ends.